Muscle pump does not enhance blood flow in exercising skeletal muscle.

The muscle pump theory holds that contraction aids muscle perfusion by emptying the venous circulation, which lowers venous pressure during relaxation and increases the pressure gradient across the muscle. We reasoned that the influence of a reduction in venous pressure could be determined after maximal pharmacological vasodilation, in which the changes in vascular tone would be minimized. Mongrel dogs (n = 7), instrumented for measurement of hindlimb blood flow, ran on a treadmill during continuous intra-arterial infusion of saline or adenosine (15-35 mg/min). Adenosine infusion was initiated at rest to achieve the highest blood flow possible. Peak hindlimb blood flow during exercise increased from baseline by 438 +/- 34 ml/min under saline conditions but decreased by 27 +/- 18 ml/min during adenosine infusion. The absence of an increase in blood flow in the vasodilated limb indicates that any change in venous pressure elicited by the muscle pump was not adequate to elevate hindlimb blood flow. The implication of this finding is that the hyperemic response to exercise is primarily attributable to vasodilation in the skeletal muscle vasculature.     

Sympathetic restraint of muscle blood flow at the onset of dynamic exercise.

Little attention has focused on sympathetic influences on skeletal muscle blood flow at the onset of exercise. We hypothesized that 1) the sympathetic nervous system constrains muscle blood flow and 2) the decline from peak blood flow is mediated by increasing sympathetic vasoconstrictor tone. Mongrel dogs (n = 7) ran on a treadmill after intra-arterial infusion of saline (control) or combined alpha(1)- and alpha(2)-adrenergic blockade (prazosin and rauwolscine). Immediate and rapid increases in hindlimb blood flow occurred at commencement of exercise with peak iliac blood flows averaging 933 +/- 79 and 1,227 +/- 90 ml/min during control and blockade conditions, respectively. At 1 min of exercise, hindlimb blood flow had decreased to 629 +/- 54 and 1,057 +/- 89 ml/min. In the absence of sympathetic vasoconstrictor tone, there was an enhanced peak blood flow at the onset of exercise. In addition, alpha-blockade attenuated the overshoot of hindlimb blood flow compared with the control condition. These data suggest that an immediate and sustained increase in sympathetic outflow restrains hindlimb blood flow at the onset of exercise and is responsible, at least in part, for an overshoot of blood flow to exercising skeletal muscle.     

Immobilization of invertase on a new type of macroporous glycidyl methacrylate

Invertase was immobilized via its carbohydrate moiety. The immobilized enzyme has a specific activity of 5500 IU g^–1, with 45% activity yield on immobilization. In a packed bed reactor, 90% 2.5 M sucrose was converted at a flow rate of 4 bed volumes h^–1. The obtained specific productivity at 40 °C of 3 kg l^–1 h^–1 is the best one so far. Long-term stability was 290 days in 2.5 M sucrose at 40 °C and at a flow rate of 3 bed volumes h^–1.     

Structure and properties of polyurethanes prepared from triglyceride polyols by ozonolysis

Ozonolysis was used to obtain polyols with terminal primary hydroxyl groups and different functionalities from trilinolein (or triolein), low-saturation canola oil, and soybean oil. The functionality of the model polyol from triolein (trilinolein) was 3.0 and that of soy polyol was 2.5, due to the presence of unreactive saturated fatty acids, while canola gave a polyol with a functionality of 2.8. All polyols exhibited a high tendency to crystallize at room temperature. The resulting waxes had melting points comparable to that of paraffin and very low viscosities in the liquid state. The polyols were cross-linked using 4,4'-methylenebis(phenyl isocyanate) to give polyurethanes. Glass transitions (T(g)) for the model-, canola-, and soy-based polyurethanes were 53, 36, and 22 degrees C, respectively. The about 30 degrees C lower T(g) of the soy-based polyurethane than that of the model polyurethane was the result not only of lower functionality but also of the presence of saturated fatty acids in the former. Polyurethane from the canola polyol had intermediate cross-linking density and properties. These polyurethanes displayed excellent mechanical properties and higher glass transition temperatures compared to polyurethanes from epoxidized and hydroformylated polyols of the same functionality, presumably due to the absence or lower content of dangling chains in the former.     

Optimizing long intrinsic disorder predictors with protein evolutionary information

Protein existing as an ensemble of structures, called intrinsically disordered, has been shown to be responsible for a wide variety of biological functions and to be common in nature. Here we focus on improving sequence-based predictions of long (>30 amino acid residues) regions lacking specific 3-D structure by means of four new neural-network-based Predictors Of Natural Disordered Regions (PONDRs): VL3, VL3H, VL3P, and VL3E. PONDR VL3 used several features from a previously introduced PONDR VL2, but benefitted from optimized predictor models and a slightly larger (152 vs. 145) set of disordered proteins that were cleaned of mislabeling errors found in the smaller set. PONDR VL3H utilized homologues of the disordered proteins in the training stage, while PONDR VL3P used attributes derived from sequence profiles obtained by PSI-BLAST searches. The measure of accuracy was the average between accuracies on disordered and ordered protein regions. By this measure, the 30-fold cross-validation accuracies of VL3, VL3H, and VL3P were, respectively, 83.6 +/- 1.4%, 85.3 +/- 1.4%, and 85.2 +/- 1.5%. By combining VL3H and VL3P, the resulting PONDR VL3E achieved an accuracy of 86.7 +/- 1.4%. This is a significant improvement over our previous PONDRs VLXT (71.6 +/- 1.3%) and VL2 (80.9 +/- 1.4%). The new disorder predictors with the corresponding datasets are freely accessible through the web server at http://www.ist.temple.edu/disprot.     

Quality of screening for diabetic retinopathy in the Rijeka region of Croatia

The aim of this study was to compare the quality of screening for diabetic retinopathy in cities of Rijeka and Zagreb, Croatia. Review of a random sample of 500 diabetic patient records and prospective ophthalmologic survey of 466 randomly selected diabetic patients in a secondary level diabetologic service in Rijeka (coastal region of Croatia). The main outcome measures were proportion of diabetic patient records with notes on ophthalmologic examination; rate of diabetic patients involved with screening for diabetic retinopathy; comparison with rates in Zagreb (Croatian capital). A total of 67% patients visited the ophthalmologist at least once after diagnosed with diabetes, and notes on ophthalmologic examination were found in only 28% patient records. Fifty percent of patients underwent an ophthalmologic examination within two years. Only one third of patients diagnosed with DM in last two years visited the ophthalmologist within this time, and 14% of patients older than 50 years never visited the ophthalmologist. Model of screening for diabetic retinopathy in Croatia works better in Zagreb than in Rijeka region, and needs certain improvements. The authors suggested modern methods of screening, the incorporation of the mechanisms of quality control, the obligatory reporting of newly diagnosed diabetic patients to the national registry, and the direct referral from diabetologist to ophthalmologist.     

Cataract surgery and intraocular lens implantation in children with juvenile rheumatoid arthritis associated uveitis

Clinical records of 6 children (7 eyes) with juvenile rheumatoid arthritis (JRA) who underwent cataract surgery with IOL implantation between January 1998 and December 2002 were reviewed. The median age at the time of cataract surgery was 8 years (range 5-14 years). The median follow up was 48 months (range 26 to 60 months). Five of six children (6 eyes) were on systemic immunosuppressive or anti-inflammatory therapy. Glaucoma was present in three eyes before surgery, and all three eyes underwent combined cataract surgery and trabeculectomy with mitomycin C. A final best corrected visual acuity of 0.5 or better was achieved in all eyes Postoperative complications included posterior capsule opacification (n = 5), glaucoma (n = 1), and cystoid macular edema (n = 1). Intraocular lens implantation in children with control of preoperative and postoperative ocular inflammation could lead to favorable visual results.     

Oral health status and temporomandibular disorders in multiple sclerosis patients

Multiple sclerosis (MS) is an inflammatory disease of unknown etiology involving the central nervous system. Certain clinical manifestations affect the oro-facial region. Three in particular should be of interest to the dentist: trigeminal neuralgia, sensory neuropathy of the trigeminal nerve and facial palsy. The aim of this study was to determine the oral health status, the frequency of subjective symptoms and temporomandibular disorders (TMD) subtype according to Research diagnostic criteria for temporomandibular disorders (RDC/TMD) among MS patients. Examinees in this study were 50 patients suffering from MS, who were at least once treated during their disease in the Clinic Hospital Center, Rijeka, Clinic for Neurology. All examinees had to meet the diagnostic criteria for clinically and laboratory confirmed MS, according to Poser. The results show the difference in mean DMFT (decayed, missing, filled teeth) between MS and the control group. The number of decayed and missing teeth was higher, but the number of filled teeth was significantly lower in MS group. Eighty-two per cent of the subjects with MS had a least one symptom of dysfunction compared with 24% of the subjects in the healthy control group. In the present study, pain, the pain during mouth opening, the difficulty with mouth opening and temporomandibular joint (TMJ) sounds were more commonly reported in the MS group than in the control group. This study shows a statistically significant excess of dental caries and temporomandibular disorders among MS patients compared with the control group. These results suggest that MS is a possible etiological factor in temporomandibular disorders.